RE: 1 GB lowmem

Rune Torgersen wrote:

linuxppc-dev-bounces+runet=3Dinnovsys.com@ozlabs.org wrote:

quoted

Hi
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I am trying to enable 1 GB of lowmem on a Freescale 8280.
In arch/ppc this was easilly done by:
CONFIG_ADVANCED_OPTIONS=3Dy
CONFIG_HIGHMEM_START=3D0xfe000000
CONFIG_LOWMEM_SIZE_BOOL=3Dy
CONFIG_LOWMEM_SIZE=3D0x40000000
CONFIG_KERNEL_START_BOOL=3Dy
CONFIG_KERNEL_START=3D0xa0000000
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This does not work in arch/powerpc. CPU hangs as soon as init starts.
Any ideas what to look at, what to change?
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The reason I want to do this is because I cannot get highmem support
to work when using CONFIG_PREEMPT_RT.
(hitting a bug_on in kmap_atomic)

=20
Scratch that. 1 GB lowmem works with vanilla 2.6.25.4, but
not at all with 2.6.25.4-rt[13]

Argh... Found it. Had to set CONFIG_TASK_SIZE to 0x80000000. Now it
works in both vaniulla an d RT kernel.
Highmem still doesn't work.